Spindle cell oncocytoma of the sella turcica with anaplastic features and rapid progression in short-term follow-up: a case report with proposal of distinctive radiologic features

Abstract

We present a rare case of spindle cell oncocytoma (SCO) of the sella turcica with malignant histologic features and rapid progression. A 42-year-old woman experienced bilateral blurred vision and was preoperatively misdiagnosed as having a pituitary macroadenoma on magnetic resonance imaging. After surgery, SCO was diagnosed by the histopathologic features of interlacing fascicles of spindle tumor cells with finely granular, eosinophilic cytoplasm. Focal anaplastic changes and necrosis were present. Immunohistochemically, the tumor cells were positive for vimentin, epithelial membrane antigen, S-100, galectin-3, and thyroid transcription factor 1. Four months later, the tumor had progressed, and second surgery with adjuvant radiotherapy was performed; the patients remains under observation. In this report, we proposed distinctive radiologic features for differential diagnosis between SCO and other pituitary tumors.

Spindle cell oncocytoma, a misdiagnosed rare entity of the pituitary – A case report with review of literature and special emphasis on the morphological differentials

“…The presenting symptoms are usually nonspecific, including visual disturbances, headaches, and panhypopituitarism, mainly due to the mass effect on the optic chiasm and pituitary gland. 3,5,7 The radiologic features of SCO are also considered to be nonspecific and are indistinguishable from a pituitary Fig. 6: Immunohistochemistry stain for S100 showed strong positivity adenoma.…”

“…7: Immunohistochemistry stain for Ki 67 showed a proliferation of 1-2% critical size. 3 They proposed that the central fibrous stellate scar causing enhancement inversions is a specific finding for SCO of the sellar turcica.…”

“…However, case reports with anaplastic features with rapid progression and recurrence are also reported. 3 The morphological differentials considered are pituicytoma, meningioma, schwannoma, solitary fibrous tumor(SFT), paraganglioma, and null cell adenoma with oncocytic change. Immunohistochemistry plays a vital role in the diagnosis.…”

“…2 However, from 2002 to 2021 March, < 50 cases have been reported in the English literature. 3 Due to their location and nonfunctional nature, these tumors are often misdiagnosed as nonfunctional pituitary adenomas. The careful histomorphological and immunohistochemical examination helps to have the correct diagnosis.…”

“…2 The highly vascular and adherent nature often makes the tumor challenging to resect. [1][2][3][4][5][6]…”